3 years, $39 million. He can opt out after 2 years, which would make it a $26 million deal. He can opt out if, after year 2, the Yankees don't pick up the option for the fourth year, which would raise the total on the contract $53 million. If the Yankees trade him, he gets a $1 million assignment bonus.
The Yankees' 40-man roster is full, so a corresponding move will need to be made to open a slot for Britton.
Since they play the Red Sox in a two-game series in London in June, they can use Britton in Britain.
Now go get Ottavino, and maybe bring back Adam Warren.